SPC: North Pole

Entrenchment – Dealing with a well-established persistent instability. Entrenchment (not a preferred operating mode) requires discipline to sustain it for the necessary time; this is the last resort short of closing operations completely.

Limit skiing to a small terrain selection assessed as having acceptable risk until the situation has clearly changed. New evidence continues to be gathered and monitored for changing conditions, but new terrain is only considered for opening if there is compelling evidence to do so (for example if an avalanche was observed that definitely removed the layer of concern).

Entrenchment mode is a successful operating strategy for persistent slab instabilities.Establish a limited base of acceptable operating terrain and be disciplined to operate only within that designated terrain as long as necessary for the persistent instability to run its course. Expect this to take longer than anticipated and do not step out into new terrain prematurely. Plan to maintain this discipline beyond the time when all evidence seems to indicate that the persistent instability is no longer a concern.

When dealing with persistent instabilities, discipline is more likely to be successful than cleverness –it is better to wait out the instability than to try to outsmart it.